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Stop Watching Sophie's Choice (And Get Some Work Done)

25 Nov 2008

I woke up this morning to Kirin Dave's cantankerous rant about how Ruby's going down the tubes. The whole post was a giant whine-fest, with the exception of the beginning, where he heaps faux past praise on Ruby to justify his complaints.

The entire post read kind of like Joe Lieberman supporting McCain: "I used to be a Democrat, but now I think Obama's in love with terrorists." Dave didn't even really attempt to be even-handed in his critique (if I can even call it a critique); he just goes after the Ruby language, interpreter, and community with the full force of his giant... rhetoric.

Let's take a look at Dave's claims:

Claim 1. Ruby's interpreter is so outdated, it's impossible to write code without it leaking memory. As evidence, he points to a case encountered by Tom Preston-Warner in his God monitor library. What Dave fails to point out is that despite his claims that Ruby 1.9 is basically useless, the last post in the thread he references informs the readers that the bug is fixed in Ruby 1.9.

He also doesn't inform the reader that many large web applications, including YellowPages.com, scribd.com, and hulu.com, not exactly tiny web sites, are running on infrastructures that depend on this "outdated" interpreter. While I'm not going to claim that the Ruby interpreter is all rainbows, it's hardly the problem that Dave claims it is.

Dave also dismisses JRuby with a wave of his hand, using the argument that it's not useful for web applications because it can't be used for scripting (which Ruby is frequently used for). This is a classic example of a red herring fallacy. The existing "terrible" Ruby interpreter works just fine for scripting, where the supposed memory leaks aren't an issue. As a result, dismissing JRuby, which solves all of his other deployment concerns, is just pure malarky.

Claim 2. Ruby is the slowest thing imaginable. I've tackled this argument with some vigor before, but suffice it to say that real-life Ruby applications must be compared against real-life PHP or Django applications, and they perform quite well. Even Rails, not exactly the fastest Ruby web framework, beats out CodeIgniter in Hello World benchmarks, and is dead even with CodeIgniter on more robust benchmarks. Comparing it with CakePHP, which is a closer feature-for-feature comparison, Rails completely destroys Cake in all benchmarks.

Merb, which takes more effort to avoid being slow, does significantly better than Rails, and beats CodeIgniter on hello world benches by around 5x. The reason for this is that despite Dave's claims that the Ruby community is stagnant, some of the worst speed offenders have been handled by native extensions that provide speedups for the community without the community having to drop into C all the time. The most recent example: ThirdBase, a library to make Ruby's date facilities an order of magnitude faster than the built-in Date class.

Because the Ruby interpreter has a fairly good C API, developers without commit access have been able to improve the speed of everything from web servers (who uses the stdlib's webrick!?) to XML parsing (why use REXML when you can use Nokogiri and gain orders of magnitude in speed). Real-life applications are simply not as slow as the benchmarks (which even Dave admits are not dispositive) would seem to imply. Real apps simply spend more time IO-waiting on things like databases or grabbing strings out of cache than in calculating the fibonacci sequence.

Claim 3. Rubinius didn't happen and JRuby... these are not the droids you're looking for... Rubinius didn't happen. Somehow, in all his bloviating, Dave didn't really address JRuby at all. Let's take a look at his hand-wave real quick:

jRuby is great, but I kind of liked the illusion of a small memory footprint–a lot of Ruby use is in scripting and starting up a “java -server” instance is not really desirable for that.

So let's take a look: JRuby has too large a memory footprint. Actually, not so much. When you take into consideration that you only need a single JVM instead of multiple processes, JRuby starts looking very competitive. In fact, when you start factoring in the impact of real threads on IO-wait, JRuby starts killing MRI.

I already addressed the other claim: Ruby is used in scripting and JRuby is thus unsuitable for it. For those cases, MRI works just fine. Even if we were to grant Dave his claim of unbeatable memory problems, scripts can handle a slow 200k leak every 10,000 seconds (the big gotcha memory leak). As a result of all the effort around alternative implementations (and spearheaded by Rubinius), JRuby and MRI are remarkably compatible. Developing on MRI (for fast startup times) and deploying on JRuby (for a rock-solid memory footprint and great concurrency handling) is viable by design.

In essence "There are no good choices for a Ruby interpreter" is straight-up not true.

Claim 4. Ruby's future is... yawn. Dave takes a look at the new features in Ruby, and based on the future of the Ruby language, decides that Ruby itself is booooring. He makes one tiny mistake when he claims that better FFI was only in alternative implementations: the aforementioned C API made it possible for wmeissner of the JRuby team to roll out a 100% compatible version of Rubinius' FFI (which they have now adopted) for Ruby 1.8.

Probably the most misleading part of this claim is ignoring all the work being done on Ruby libraries. I can be competitive with Rails from time to time, but even I'm not going to claim that Rails is no longer producing good work. And Merb is fairly well acknowledged for innovation around these parts. Dave says:

And what do I have to look forward to in the Ruby world? Essentially the same promise that I heard in late 2005, “Christmas will bring a faster ruby.”

This assumes that the only interesting things happening around a library are related to its core interpreter or the core language. While Ruby 1.9 does see some improvements to the complaints that he raised, and JRuby flat-our resolves them, Dave's fundamental mistake is here. By assuming that the only way the community around a language can get better is by improving its core, he is ignoring reality: there are tons of exciting developments around Ruby that are being pushed by its users.

Dave closes by saying:

People will leave trying to stake out The Next Big Thing™, bleeding the Ruby talent pool dry and making it even less capable of recovering from these bad fortunes.

I predict the opposite. The Ruby talent pool will continue to grow, and we will continue to produce new, innovative, and exciting projects. JRuby will continue to improve and Rubinius will be released, sparking a new Ruby speed war that will lead to the faster Ruby that so dominates Dave's dissatisfaction. And the Ruby community will continue to learn from other languages, like Python and Erlang. It's only going to get better from here.